title: Differential age-associated regulation of clusterin expression in prostate lobes of brown Norway rats.
abstract: BACKGROUND
  Serum androgen concentrations decline with age in male Brown Norway rats and castration induces apoptosis of luminal secretory epithelial cells in the ventral but not in the dorsal and lateral prostate lobes. Clusterin has been described as an androgen-repressed gene and a protein with either anti- or pro-apoptotic actions.
  
  
  METHODS
  We measured clusterin mRNA and protein levels, the effects of aging and castration on clusterin protein levels and clusterin immunolocalization within the prostatic ductal network in the prostate lobes of young and aged rats.
  
  
  RESULTS
  Whereas levels of clusterin mRNA and protein expression measured by RT-PCR and Western blot, respectively, were higher in the ventral and lateral lobes of aged (24 months) compared to young (4 months) rats, no age-dependent differences were observed in the dorsal lobe. Clusterin expression was localized by immunohistochemistry exclusively to the proximal duct segment of young rats, but extended to the distal segment of the ventral and lateral lobes of aged rats. Despite an age-related decrease in serum testosterone concentration, clusterin gene expression was not altered in the dorsal lobe. After castration, levels of clusterin expression increased significantly in the ventral and lateral lobes despite the absence of epithelial cell apoptosis in the latter. In castrated rats, clusterin expression extended throughout the proximal-distal duct regions of the prostate lobes of young and aged rats.
  
  
  CONCLUSIONS
  Regulation of clusterin expression in the prostate lobes of aging rats appears complex and is neither directly repressed by androgen nor dependent on apoptotic-induced stress.
authors.affiliation: Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland 21205-2103, USA.
authors.forename: Josephat
authors.initials: J
authors.lastname: Omwancha
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Anway
authors.forename: Terry R
authors.initials: TR
authors.lastname: Brown
mesh_terms: D000375:Aging / Q000235:genetics*; D000728:Androgens / Q000097:blood; D000818:Animals; D017209:Apoptosis; D051152:Clusterin / Q000235:genetics*; D004247:DNA / Q000235:genetics; D017931:DNA Primers; D004847:Epithelial Cells / Q000502:physiology; D018507:Gene Expression Regulation, Developmental; D008297:Male; D009919:Orchiectomy; D011467:Prostate / Q000254:growth & development / Q000502:physiology; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D011914:Rats, Inbred BN / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D000728:Androgens; D051152:Clusterin; D017931:DNA Primers; D012333:RNA, Messenger; D004247:DNA